Proud grandma! Tina Knowles gave an update on Beyoncé and Jay Z's twins, Rumi and Sir, in an exclusive interview with Us Weekly on Thursday, September 28.

"They are amazing," the fashion designer, 63, told Us at the Habitat For Humanity Builder's Ball in Beverly Hills. "They're very young but they like to touch and they’re adorable and just beautiful and healthy and I’m just so happy."

Beyoncé, 36, and the rapper, 47, welcomed their second daughter and first son in June. Jay Z opened up about their names during the Rap Radar podcast last month. "Rumi is our favorite poet, so it was for our daughter," he explained at the time. "And then Sir was, like, man, come out the gate. He carries himself like that. He just came out, like, Sir."

As Us Weekly exclusively reported, Blue Ivy, 5, was "so excited" about the new additions.

"She's doing amazing! She’s a big sister and she feeds them and she's excited," Tina added to Us at the Beverly Hilton. "And she feels responsible for them being here because she prayed for them."

The role of big sister comes naturally for Blue. "She’s always picking out cute clothes for them," an insider told Us earlier this month. "She’ll run up to see how they’re doing. She’s always checking on them and helping take care of them."